Pest control professionals are often called upon to address the presence of unwanted indoor spiders. Unlike economically significant pests, like termites, carpenter ants and carpet beetles, spiders do not damage structures or objects found indoors. And unlike medically significant pests, like mites, bed bugs, wasps, and ticks, the vast majority of spider pest species in the United States are not considered medically harmful to humans.

Incidents involving large amounts of spiders infesting indoor areas is not unheard of, but generally, spiders rarely “infest” inhabited homes and buildings. Most indoor spider infestations occur within structures that are rarely frequented by humans. For example, hundreds, and even thousands of spiders have been reported as infesting garages, sheds, abandoned homes and storage areas, but infestations of this magnitude rarely occur in busy living conditions.

Spiders are considered pests solely because their appearance inspires fear and disgust in humans. The types of  insects and spiders that are eradicated from homes on account of their appearance are considered “aesthetic pests”. While spiders are generally categorized as aesthetic pests only, most other arachnid and insect pests fit more than one category of pest. Cockroaches, for instance, are categorized as “pests of medical importance”, “nuisance pests”, and “aesthetic pests”. One group of scary-looking spiders that often appear within Massachusetts homes are “grass spiders”. These spiders belong to the Agelenopsis genus and they are often found indoors due to their preference for backyard conditions.

Grass spiders are also commonly referred to as funnel-web weavers due to the funnel-shaped webs that they build on grassy lawns. Agelenopsis kastoni, Agelenopsis potteri and Agelenopsis utahana are the three most commonly encountered grass spiders in Massachusetts. All three of these species look similar, and they are often mistaken for wolf spiders on account of their relatively large size and tan to dark brown-colored bodies. However, unlike wolf spider bites, bites from grass spiders never lead to medical issues. Grass spiders emerge in residential lawns during the spring season where they continue to maintain a significant presence during the summer and fall.

Have you ever found a spider in your home or garden that was covered in hairs?